Subcoracoid impingement and subscapularis tendon: is there any truth?

Magnetic resonance imaging based coracoid process morphology and its associations with isolated subscapularis tendon tears in Chinese patients

OBJECTIVES

This study aims to assess the association between isolated subscapularis tears and coracoid morphology using magnetic resonance imaging (MRI) and to calculate the optimal cut-off values of the significant predictor to predict subscapularis tears.

PATIENTS AND METHODS

Between January 2018 and December 2022, a total of 60 patients (29 males, 31 females; mean age: 58.4±8.4 years; range, 18 to 80 years) diagnosed with subscapularis tendon tears who were treated as Group A and 60 patients (29 males, 31 females; mean age: 46.8±11.5 years; range, 18 to 80 years) without subscapularis tendon tears who were treated as Group B were included. Axial coracoid-humeral distance (aCHD), sagittal coracoid-humeral distance (sCHD), coracoid overlap (CO) and coracoid angle (CA) of all patients were measured. Logistic regression was used to investigate the association between subscapularis tears as variables including aCHD, sCHD, CO and CA. Receiver operating characteristic curve analysis was used to determine the diagnostic values of coracoid morphology for subscapularis tears.

RESULTS

The mean values of CO, aCHD and sCHD in Group A were 22.16 mm, 5.13 mm, and 5.56 mm, respectively. The mean values in Group B were 16.99 mm, 7.18 mm, and 7.29 mm, respectively. The degree of CA in Group A was 95.81 and 111.69 in Group B. The differences in the above measurement values were significant between two Groups. The CO was found to be associated with higher odds of subscapularis tears. The optimal cut-off value of CO was 19.79 mm.

CONCLUSION

Based on our study results, CO is positively associated with isolated subscapularis tears. In addition, coracoid bursa effusion, cysts in the lesser tuberosity or a tear and malposition of long head of the biceps tendon on MRI may predict the presence of a clinically significant subscapularis tear.

Is it the subcoracoid impingement or the subacromial impingement that tears the subscapularis tendon? A comparison of the MRI findings of the operated and healthy shoulders of the patients

BACKGROUND

: The purpose of this study is to investigate whether the etiological factors accepted as causes of idiopathic subscapularis tears are true or not when the comparison is made with the opposite side healthy shoulder of the patients who underwent arthroscopic repair for an isolated subscapularis tear.

METHODS

Sixteen patients who underwent shoulder arthroscopy between February 2016 and January 2018 and were diagnosed with isolated subscapularis tear were evaluated. The coracohumeral distance (CHDax), coracoid overlap (CO), and tuberculum minus cysts (TMC) were evaluated on the axial images of the MRI studies while the acromiohumeral distance (AHDsag), CHDsag, and subscapularis tendon slip number (STSN) on the sagittal oblique images and the AHDcor and SLAP lesion on the coronal oblique images. Degeneration of the coracoacromial ligament was evaluated during arthroscopy.

RESULTS

The mean CHDsag (11.26-10.08), CHDax (10.63-9.98), CO (14.2-15.43), AHDsag (8-7.66), and AHDcor (7.65-7.68) measurements (operated side-healthy side, respectively) were statistically similar (p > 0.05). No statistically significant difference was found between TMC and STSN in healthy and operated shoulders (p > 0.05). There was mild coracoacromial ligament fraying in 4 (25%) and obvious coracoacromial ligament fraying in 8 (50%) which indicated subacromial impingement in 75% of the patients.

DISCUSSION

The parameters of the coracoid process did not reveal any significant difference between the operated (for an isolated subscapularis tear) and opposite-side healthy shoulders of the patients. However, coracoacromial ligament degeneration was present in 75% of the patients.

Subcoracoid Impingement – A Global View

Modifications in joint anatomy on both soft and bony tissue level play a key role in subcoracoid impingement syndrome. The diagnostic is primarily clinical and is based on patient history and functional tests. Imaging tests support, but do not establish the diagnostic. Approach can take the form of targeted exercises with progressive load, or that of invasive surgery.

Shoulder pain has a diverse etiology which derives from the complex local anatomy which includes the clavicle, acromion, coracoid process and humeral head, the soft tissues surrounding this area, in particular the rotator cuff, but can also be unrelated to all of the above and be a reflection of a pathology located in the neck, arm or trunk, or adjacent visceral organs. More often, it is the manifestation of a traumatic episode or an anatomical anomaly, or it can be secondary to inflammation, tumors, or surgery.

It is the third most common musculoskeletal complaint presenting to physiotherapy, and largely impacts both an individual’s quality of life and the public health system.

Coracoid impingement syndrome can present itself as a cause of rotator cuff disease, but its role is not fully established yet. It is less prevalent than subacromial impingement, can coexist with it, and therefore should be considered into the differential diagnosis of anterior shoulder pain when a patient presents themselves with activity related anterior shoulder pain.

The anterior translation of the humeral head leads to a decrease in the coracohumeral distance in subscapularis tear

A total of 297 patients who classified as subscapularis (SC) tears through arthroscopic evaluation were retrospectively enrolled, and Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The coracohumeral distance (CHD) and humeral head anterior translation (HHAT) were measured on magnetic resonance imaging. Our study demonstrated that the anterior translation of the humeral head is related with a decrease in the coracohumeral distance in subscapularis tear. Although, correlation between radiologic parameters (coracohumeral distance and anterior translation of the humeral head) and severity of subscapularis tear was note detected.

Level of evidence

Level IV, retrospective study.

Surgical Outcomes after Arthroscopic Single Row Anchor Repair for Subscapularis Tears Concomitant with Injury of the Long Head of the Biceps Tendon

Objective

To analyze the clinical effects of single row anchor in repairing tears of the subscapularis muscle combined with the long head of the biceps tendon (LHBT) injury under arthroscopy.

Methods

From June 2016 to June 2017, the clinical data of 32 patients with subscapularis combined with biceps tendon injury were retrospectively analyzed. Preoperative MRI examination of the shoulder joint was performed to evaluate tendon injuries, and the subscapularis muscle was repaired with single row anchor under arthroscopy, and tenotomy or tenodesis was performed on the long head tendon of the biceps humerus in the intertubercular groove. The range of motion and the functional score of the shoulder joint before and after the operation were evaluated. All patients were followed up for at least 24 months.

Results

The mean follow‐up period was 28.8 months (range, 24–34 months). No infections occurred during the follow‐up period. The patients’ follow up exams showed significant improvement in postoperative shoulder joint flexion, external rotation, and internal rotation (P < 0.01), and the postoperative shoulder function American Society of Shoulder and Elbow Surgery Shoulder Joint Score (ASES; 80.6 ± 7.6) was significantly higher than the preoperative score (P < 0.01). The visual analog scale score (1.8 ± 0.8) was significantly lower than that before surgery (P < 0.01). The constant score (80.5 ± 7.4) was significantly higher than preoperation (P < 0.01). There was no significant difference in shoulder joint score between the tenotomy and tenodesis groups (P > 0.05). Preoperative and postoperative scores were, respectively: visual analog scale score (1.7 ± 0.9 vs 1.8 ± 0.0.8) ASES score (81.3 ± 7.9 vs 80.1 ± 8.0) and constant score (80.9 ± 8.0 vs 80.1 ± 6.9).

Conclusion

Using single row anchor under arthroscopy to repair subscapularis combined with long head of biceps tendon injury yielded good results and high tendon healing rates were obtained.

Predictors of safety margin for coracoid transfer: a cadaveric morphometric analysis

Background

The purpose of this study was to investigate the relationship between the bone length available for coracoid transfer without coracoclavicular ligament injury and the distance from the coracoid tip to the attachments of the coracoacromial ligament or pectoralis minor. We hypothesized that cadaver height and the soft tissue attachments on the coracoid process were predictive factors for sufficient bone length for coracoid transfer.

Methods

This study included 28 shoulders from Japanese cadavers: 19 male and 9 female. The distance from the coracoid tip to the distal attachment of the coracoclavicular ligament and the anterior and posterior margins of the coracoacromial ligament or pectoralis minor on the coracoid process were measured.

Results

The mean available length for coracoid transfer was 24.8 ± 3.4 mm. There was a significant difference in length between male and female subjects, being 26.0 ± 2.9 mm and 22.2 ± 3.0 mm, respectively (p = 0.004). High positive correlations were found between the length of the coracoid transfer and cadaver’s height (r = 0.48, p = 0.009) and the distance from the coracoid tip to the anterior coracoacromial ligament attachment (r = 0.63, p < 0.001). The receiver operating characteristic curve area under the curve for cadaver height was 0.72 while that for distance from coracoid tip to anterior coracoacromial ligament was 0.88 when predicted for a sufficient length for coracoid transfer > 25 mm.

Conclusions

Our findings will aid surgeons in preoperative planning and performing of osteotomy of the coracoid safely by predicting the available length of coracoid bone graft.

Radiological Variabilities in Subcoracoid Impingement: Coracoid Morphology, Coracohumeral Distance, Coracoglenoid Angle, and Coracohumeral Angle

BACKGROUND The aim of this study was to investigate the effects of coracoid morphology, coracohumeral distance, coracoglenoid angle, and coracohumeral angle variabilities on subcoracoid impingement development using magnetic resonance imaging (MRI). MATERIAL AND METHODS A total of 200 patients (87 males with mean age of 51.1±15.2 years and 113 females with mean age of 52.6±10.7 years) undergoing shoulder MRI were included in this retrospective study. All MRI studies were performed with standard positioning. Coracoid morphology and subscapularis tendon were evaluated. Coracohumeral distance, coracoglenoid angle and coracohumeral angle were measured in all subjects. One-way ANOVA was used to assess the difference between the groups. For binary comparisons, Tukey post hoc analysis was done. Pearson correlation analysis was performed between variables. RESULTS Type C coracoid was more frequent in the tendinosis and tendon tear groups. There was a significant difference between type C coracoid and the other coracoid types for coracohumeral distance values (P=0.016). There was a statistically significant decrease in coracoglenoid angle values and coracohumeral distance in patients with subscapularis tendon pathologies (P=0.000). A statistically insignificant increase in coracohumeral angle values was found in the subscapularis tendon pathologies. There was a positive correlation between coracohumeral distance and coracoglenoid angle (R=0.749 P=0.000). There was a negative correlation between coracohumeral distance and coracohumeral angle (R=-0.668 P=0.000) and between coracoglenoid angle and coracohumeral angle (R=-0.605 P=0.000). CONCLUSIONS In subscapularis tendon pathologies, decrease in coracohumeral distance and coracoglenoid angle was observed. A new approach uses coracohumeral angle to evaluate subcoracoid impingement. A statistically insignificant increase in coracohumeral angle was noted.

Anatomic Study of Subcoracoid Morphology in 418 Shoulders: Potential Implications for Subcoracoid Impingement

Background:

Subcoracoid impingement has been implicated as a cause of anterior shoulder pain and subscapularis tendon tears.

Purpose/Hypothesis:

The purpose of this study was to evaluate the bony anatomy of the coracoid process and the subcoracoid space. We hypothesized that age-related changes that may contribute to subcoracoid impingement occur in the subcoracoid space.

Study Design:

Descriptive laboratory study.

Methods:

In total, 418 skeletal shoulder specimens were included in this study. We utilized 214 shoulders from a young cohort (25-35 years of age) and 204 shoulders from an older cohort (>55 years of age) for comparison. We evaluated several morphological characteristics of the coracoid process and the subcoracoid space: coracoid width, coracoid shape, coracoid thickness, and subcoracoid distance. Each coracoid was observed for the presence of spurring or other morphological changes.

Results:

The mean anteroposterior (AP) thickness of the coracoid tip was 7.9 and 9.4 mm in our young female and male cohorts, respectively, while the mean AP thickness was 8.1 and 9.7 mm in our older female and male cohorts, respectively. The coracoid tip was hooked in 31 of 108 young female shoulders compared with 55 of 102 older female shoulders, and the coracoid tip was hooked in 25 of 106 young male shoulders compared with 45 of 102 older male shoulders. The mean subcoracoid distance in neutral rotation was 14.8 and 12.5 mm in young and older female shoulders, respectively, while the mean subcoracoid distance in internal rotation in these same cohorts was 8.7 and 7.0 mm, respectively. The mean subcoracoid distance in neutral rotation was 14.8 and 13.3 mm in young and older male shoulders, respectively, while the mean subcoracoid distance in internal rotation was 8.6 and 8.1 mm in young and older male shoulders, respectively.

Conclusion:

The principal findings of our study demonstrate that anatomic changes implicated in subcoracoid impingement may be developmental and worsen with age. The subcoracoid space was narrower in our older cohort of shoulders. Additionally, these older shoulders also had a greater AP width and a more hooked coracoid compared with young shoulders.

Clinical Relevance:

Narrowing of the subcoracoid space has been shown to be implicated as a cause of anterior shoulder pain and subscapularis tendon tears. This is the first study to show that the morphological changes implicated in subcoracoid impingement become more prevalent with age. This may help to explain the increasing prevalence of subscapularis tendon tears in older patients. Furthermore, subcoracoid decompression may be seen as an option for older patients with anterior shoulder pain and subscapularis tendon tears.

Three-Dimensional Morphometric Analysis of the Coracohumeral Distance Using Magnetic Resonance Imaging

There have been no studies investigating three-dimensional (3D) alteration of the coracohumeral distance (CHD) associated with shoulder motion. The aim of this study was to investigate the change of 3D-CHD with the arm in flexion/internal rotation and horizontal adduction. Six intact shoulders of four healthy volunteers were obtained for this study. MRI was taken in four arm positions: with the arm in internal rotation at 0°, 45°, and 90° of flexion, and 90° of flexion with maximum horizontal adduction. Using a motion analysis system, 3D models of the coracoid process and proximal humerus were created from MRI data. The CHD among the four positions were compared, and the closest part of coracoid process to the proximal humerus was also assessed. 3D-CHD significantly decreased with the arm in 90° of flexion and in 90° of flexion with horizontal adduction comparing with that in 0° flexion (P<0.05). In all subjects, lateral part of the coracoid process was the closest to the proximal humerus in these positions. In vivo quasi-static motion analysis revealed that the 3D-CHD was narrower in the arm position of flexion with horizontal abduction than that in 0° flexion. The lateral part on the coracoid process should be considered to be closest to the proximal humerus during the motion.

Idiopathic heterotopic ossification of bilateral subscapularis tendons: illustration of a rare entity and a concise literature review

Ossification of the subscapularis tendon is an extremely uncommon, poorly described lesion with little known about its etiopathogenesis and clinical significance. To the best of our knowledge, only three cases of this entity have been reported till now, which were all unilateral. The authors present first case of ossification of bilateral subscapularis tendons in a 57-year-old male and hope that with increase in the number of reported cases, proper guidelines for management of such cases can be formulated.